This chapter is from the book

This chapter is from the book

Installing or Reinstalling Mac OS X

There are three situations in which you will want to install or reinstall Mac OS X:

Mac OS X has never been installed on your Mac. Presumably, you purchased a retail version of Mac OS X, and you now want to install it.

You erased a drive on which Mac OS X was installed (perhaps because it contained corrupted data you could not fix), and you now want to reinstall Mac OS X.

Mac OS X is installed on your drive, but you want to upgrade to a major new version (such as when going from Mac OS X 10.3 Panther to Mac OS X 10.4 Tiger), or you want to reinstall a version already installed (perhaps in hopes of eliminating suspected problems with the currently installed copy).

The primary way to install or reinstall Mac OS X is via the Mac OS X Install CDs (or DVD)—which either came with your computer or you purchased separately. In some cases, you may also want to use the Restore Software CDs/DVD that came with your computer. (Note: On newer Macs with DVD drives, you will have only a single DVD that serves as both a Mac OS X Install disc and a Software Restore disc.) Finally, in those cases where you are installing an updated version of Mac OS X over an existing version, you may be using a Mac OS X Update CD instead of an Install CD. I discuss all of these variations in the sections that follow.

The Mac OS X Install disc(s)

The Mac OS X Install software is provided on either CD or DVD. For Mac OS X 10.4 Tiger, the retail version is sold only as a DVD. If you need to have a CD version, you can order it from Apple for $9.95 (see this Web page for details: www.apple.com/macosx/upgrade). Note that at the time of this writing, Apple had an official deadline of December 22, 2005, to make such an exchange. However, that was an extension of a previous deadline of July 9, 2005, so it's possible that Apple may end up further extending the deadline. On newer Macs—which come with optical drives that can read DVDs—Apple ships a bootable DVD that contains both a Mac OS X installer and a more comprehensive installer that will restore all the original software (including the OS and third-party applications) that came with your Mac.

Older Macs—especially those that didn't include an optical drive that can read DVDs—include similar Install content on three or four CDs: Install Disc 1, Install Disc 2, Install Disc 3, and possibly Install Disc 4. The main installation of Mac OS X software takes place from Disc 1. Disc 2 includes numerous additional .pkg files in its Packages folder—including those that contain the software for iCal, iMovie, Microsoft Internet Explorer, iPhoto, iSync, iTunes, and StuffIt Expander—as well as files for additional printer drivers and for foreign language support. Disc 3 contains the X11 software, Additional Speech Voices, more printer drivers, and a few other components.

Figure 3.3 This is the window that appears when you launch the Install Mac OS X application from a Mac OS X Install DVD.

The rules for using the DVD versus CD version of the Install disc(s) are largely the same. The major exception is that if you are installing from CDs, after installing Mac OS X from Disc 1 and restarting your Mac you will be prompted to insert the remaining discs to finish the installation. Note: If you do a Custom Install (as described later in this chapter) and deselect the software contained on Discs 2 and 3, you will not be prompted to insert these discs.

In the discussions that follow, I typically assume you're using an Install DVD.

Xcode Tools

The retail version of Tiger includes the Xcode Tools installer package on the Install DVD. However, it does not get installed as part of the general Tiger installation. You need to install it separately. Because some of the software is of general value beyond the needs of developers, I recommend installing it.

See

"Take Note: Developer Software," in Chapter 2, for more details on obtaining and installing this software.

Startup from the Mac OS X Install disc

As you would expect, you start the installation process by using the Mac OS X Install DVD (or Disc 1 of the CD set). To do so, insert the DVD and wait for it to mount. Next, double-click the Install Mac OS X icon, which should be visible in the window that opens by default when the disc mounts. (Note: On Restore discs, it's in the Welcome to Mac OS X folder that's visible in this window.) In the window that appears, click the Restart button. Next, assuming you're running Mac OS X already, you will be prompted to give your administrator password. Do so, and your Mac will restart, booting from the Install disc.

Alternatively, you can start up from the DVD by accessing the Startup Disk System Preferences pane, selecting the DVD, and clicking the Restart button. Finally, you can boot directly from the CD by inserting it at startup and holding down the C key.

On restart, the gray Apple logo screen will appear, followed by a blue screen and the launch of the installation process. (Note: If you have a Mac with built-in Bluetooth, and your Mac doesn't detect a mouse or keyboard connected to the USB port, you'll first see the Bluetooth connection utility; after pairing with your Bluetooth mouse and/or keyboard, the installation process will begin.)

As the first step of the installation process, the Installer asks for your preferred language. This determines the language used in the remaining windows as well as the main language used by Mac OS X after it is installed. After selecting it, you'll see the text "Preparing installation," followed by the launch and appearance of the Installer utility's Introduction ("Welcome to the Mac OS X Installer") pane.

Before you go any further, look at the menus available in the Installer utility. A number of them provide options that are of special interest.

Installing Mac OS X Without Starting Up from the Install Disc? Maybe...

To install Mac OS X on a volume other than the current startup volume, you don't necessarily have to restart from the Mac OS X Install disc. Instead, mount the disc and go to the /System/Installation/Packages folder (not found in the System folder on a hard drive running Mac OS X), which contains all the .pkg files used by the Mac OS X Install disc. From within this folder, locate the OSInstall.mpkg file and then double-click it to launch the Installer utility. You should now be able to install the software.

Note, however, that you do this at your own risk: I've seen cases where it hasn't worked. The safest bet is to start up from the disc.

The Installer menu

Only one command is important in this menu:

Quit Installer

If you select this command before you install Mac OS X, a window will appear, asking if you are sure you want to quit the Installer. Your choices are Restart, Startup Disk, and Don't Quit. Choosing Startup Disk launches the same pane that appears when you choose the Change Startup Disk command from the Utilities menu (below). If you choose Restart, your Mac will simply restart without any changes being made to your hard drive.

The File menu

The File menu also contains only one important command:

Show Files

You may not be able to choose this command from the initial Installer display; instead, you can only access it later—exactly when will depend upon the installation you're performing (that is, full install or update). The command is likely to be active by the time the Select a Destination pane appears and certainly no later than after the installation has completed (and before you restart).

If you choose this command, you will get a list of every file that gets installed by the current Installer setup and the exact folder locations in which each file will be placed. You can save this list as a text document. Although this information is not critical for the initial installation, it will become of more interest when you update the OS and want to see what files the updater installed.

The Utilities menu

The Utilities menu that appears when using current Mac OS X Install discs combines a number of utilities found in the Installer menu of older discs, as well as a few new items of particular interest to troubleshooters. Choosing an item from this menu launches one of the separate utilities located on the disc; to exit any utility and return to the main Install pane, choose the Quit command from the application menu. The included utilities are the following:

Startup Disk

This utility, which functions much like the Startup Disk pane of System Preferences, comes in handy if you can't get your Mac to start up from a particular hard drive or get it to shift to an alternative bootable hard drive as its default choice. By selecting this command, you can specify any currently available bootable drive as the default. Once you've done this, click Restart to reboot the Mac using that drive.

Reset Password

If you've already installed Mac OS X, you can use this command to enter a new password for any Mac OS X user on any mounted Mac OS X volume—an important back door of last resort in case you cannot recall your own password. Click Save to save your changes.

This arrangement also represents an obvious security weakness, since it means that anyone with a Mac OS X Install disc can change your password to gain access to your system (although you can set an Open Firmware password to prevent this, as described in Chapter 5). The security risk is the tradeoff for the ability to recover from a forgotten password.

To change a password, you first need to select the volume containing the user account whose password you wish to change. The resulting user list (the pop-up menu) includes all of the user accounts you've set up, plus the root user (if enabled). After choosing a user, enter a new password (twice, for verification) and, if desired, a new password hint. Then click the Save button to save the new password. When finished, quit the Reset Password utility.

You can access the Reset Password command only if you're starting up from an Install disc. If you launch the Installer application from a hard drive, this option will not appear. In addition, you cannot launch the Reset Password utility directly and use it—it can be used only if your computer is booted from the Install disc.

See

"Logging in as root," in Chapter 4, for more on the Reset Password command.

Disk Utility

This command launches the same Disk Utility application that you'll find in the Utilities folder on your Mac OS X volume. After choosing a volume on the left, you can select First Aid (used to repair a disk) or a variety of other options to reformat or partition your drive. I cover Disk Utility in more detail later in this chapter and again in Chapter 5. For an overview of what is available via Disk Utility, see "Disk Utility" in Chapter 2.

In general, you will not need to use Disk Utility at this point—with one exception. The default setup for a drive, as shipped from Apple, is to have one partition. Should you want to have two or more partitions, you will need to use Disk Utility to set up the additional partitions.

See

"Take Note: Why and How to Partition," below, for information on how and why you would want to partition a drive when using Mac OS X.

Chapter 5 for more on startup issues, including using passwords and Disk Utility.

System Profiler, Network Utility, Terminal

These commands, like Disk Utility, launch their respective utilities from within the Installer. As with Disk Utility, it's rare that you would need to use any of these utilities during an installation of Mac OS X. The primary reason for their inclusion here is for subsequent troubleshooting, especially if your problem prevents you from starting up from your hard drive.

See

"System Profiler," in Chapter 2, for more information on this utility.

Chapter 8, for more on Network Utility.

Chapter 10, as well as numerous other places throughout the book, for coverage of Terminal.

Why and How to Partition

Partitioning a hard drive means dividing it into two or more separate volumes. Each volume in turn mounts separately when you launch your Mac. In most respects, the volumes behave just as if you had two (assuming you made two partitions) separate hard drives (rather than just one). The only times it will be apparent that just one hard drive is at work are when the hard drive fails or if you need to reformat it.

All drives ship from Apple with just one partition. Thus, if you want two or more partitions, you must create them yourself. Using Mac OS X software, changing the number of partitions on a drive requires erasing its contents. Thus, anything on your drive that you want to save will need to be backed up first—which is precisely why I recommend partitioning a drive the day you unpack your new Mac. There will be nothing to back up because you haven't used it yet—which means the process will be simplified considerably.

Why partition?

A primary benefit of partitioning is that if you make both volumes startup volumes (in other words, you install Mac OS X on both partitions), you have two ways of starting up your Mac from the same drive. If you're having trouble with volume A, for example, and you need to restart from another volume to fix the problem, volume B is ready to go. You don't necessarily need to seek out a CD or other external medium.

You can also use a second partition to install a different version of Mac OS X. For example, if you're currently running Panther, you could install Tiger on a second partition, to test it out, before deciding whether to install it on your main partition.

Even if you don't choose to make the second partition bootable, you can still use it to store backups of important personal files (such as documents and photos) that are stored on the first partition. Or (as I discuss more in Chapter 6), you can choose to store Mac OS X's virtual-memory swap files or even your entire home directory on the second partition (to protect them from problems with the boot volume).

Note: The best and safest backup option is to move or copy these items to another drive altogether, not just another partition of the same drive. If the drive fails completely for some reason, such a failure is likely to affect both partitions.

In any case, you can erase one partition (for example, via the Installer's Erase and Install option) without erasing any others. The day may come, for example, when Mac OS X files get so messed up that the only solution is to erase the volume and start over. With two partitions, you can erase the boot partition without losing whatever is on the second partition.

Mac OS 9 on the second partition. If you have a Mac that's still capable of booting from Mac OS 9, you can make the second partition a Mac OS 9 boot volume. In fact, the ideal arrangement is to maintain two Mac OS 9 System Folders: one on a separate partition from Mac OS X and a second on the same partition as Mac OS X. Since some files work in Mac OS 9 directly but not in Classic (primarily extensions and control panels—for more on this, see the online Classic chapter), with only one copy of Mac OS 9 installed, you may have to choose between giving up on these programs so that you can use Classic in Mac OS X or keeping them and giving up on Classic. Having two Mac OS 9 System Folders allows you to use one version of Mac OS 9 (typically the one on its own partition) when you want to boot from Mac OS 9 and the other (the one on the Mac OS X partition) when you want to launch Classic—you can have your cake and eat it, too!

A related benefit: If you hold down the Option key at startup (as discussed in Chapter 5), you can select a startup volume. If Mac OS X and Mac OS 9 reside on the same partition, however, only the most recently booted OS will appear. If you cannot start up from Mac OS X, for example, you will not be able to use this method to switch to starting up from Mac OS 9, because the Mac OS 9 System Folder will not be listed as an option. Your only option is to start up from a CD or DVD. With Mac OS 9 and Mac OS X on separate partitions, the Mac OS 9 choice would be available, and you could bypass the need for the disc—helpful if you need to boot in Mac OS 9 to back up files before erasing a troublesome Mac OS X volume.

Mac OS X on the second partition. Alternatively, especially for Macs that cannot boot from Mac OS 9, you can have the second partition be a second Mac OS X boot volume—for example, populated with maintenance and repair utilities. (In this case, I would boot from the second partition only in emergencies, since regularly switching back and forth between two Mac OS X installations can lead to confusion and problems, such as permissions errors that prevent files from opening.)

Bottom line: I recommend partitioning a drive as long as your hard drive is large enough to accommodate more than one partition. If you hard drive is 60 GB or more, you should have more than enough room for at least two partitions.

How to partition?

The following are some general instructions for dividing a drive into two partitions. Remember: Doing so will erase all existing data on any and all current partitions for this drive.

After starting up from a Mac OS X Install disc (as described in the main text), from the Utilities menu select the Disk Utility command.

Select the drive you want to partition from the list in the left column of the Disk Utility window.

Click the Partition button.

From the Volume Scheme menu, select "2 partitions" (assuming you want only two partitions).

Drag the divider between the partitions to adjust their sizes as desired.
Mac OS X works best when you have a healthy amount of unused hard-drive space on the boot volume. Thus, in choosing a partition size, make sure that you'll have at least several gigabytes of unused space after you've completed the installation. If this is not the case, I recommend getting a larger hard drive or not partitioning.

Click the first of the two partitions. In the Volume Information section, enter a name in the Name text box and select a drive format—most likely Mac OS Extended (Journaled).
Now click the second partition and repeat the process.
Note: If you intend to boot from Mac OS 9, make sure the Mac OS 9 Drivers Installed option is selected, if such an option is present. If your Mac cannot boot from Mac OS 9 (as is the case for all currently shipping Macs), you will not get this option.

Click the Partition button.

Now that the partitions have been created, the next thing you'll likely want to do is install Mac OS X on one partition, including restoring all the additional software that was on your Mac when it first arrived. Mac OS 9 may not have been installed on your drive at that time. Still, it should be available via the Restore software. Refer to the sections on installing and restoring software, in the main text of this chapter, for details.

Finally, after restarting from your newly installed Mac OS X volume, if you want Mac OS X on the second partition, don't drag and drop the Mac OS X System software from one partition to the other. This will not result in a bootable partition. To install Mac OS X on the second partition, use the Installer a second time.
If you instead want Mac OS 9 on the second partition, copy a Mac OS 9 System Folder—as well as the Applications (Mac OS 9) folder, if you want—to the second partition, via drag and drop, so that you have a separate copy of the System Folder there. You can delete the original Mac OS 9 software after you've copied it, should you want only one Mac OS 9 system on your drive.

Partitioning without erasing. There are now utilities—such as Prosoft's Drive Genius (www.prosofteng.com)—that can partition a drive on the fly or even modify the size of an existing partition without requiring that you erase its contents. Always back up your drive before using one of these utilities, in case something goes wrong. I can tell you that I have used Drive Genius and it worked just fine.

Note: These utilities are at least partly based on Apple's Unix pdisk command, included as part of Mac OS X.

The Startup Disk, Reset Password, Disk Utility, Terminal, System Profiler, and Network Utility applications are stored in the Utilities folder inside the Applications folder stored at the root level of the CD or DVD. When you select one of these applications from the Utilities menu, the Installer launches the copy of the utility found there. This /Applications/Utilities folder also contains the Open Firmware Password Utility (discussed in Chapter 5).

The Window menu

The Window menu contains one last command of note:

Installer Log

If you choose this command, a log window will open, displaying all actions and errors (if any) that occur while Mac OS X is being installed.

In most cases, you can ignore any reported errors, because they don't imply that you won't be able to install Mac OS X. If you really trip over a show-stopping error, you will almost certainly be warned about it directly, via a message alert in the Installer window. In other words, you won't need to check the log. The log may prove useful as a diagnostic aid, however, if a problem occurs for which no other explanatory message appears. You can choose at any time to save the log to your hard drive by clicking the Save button.

Introduction

Returning to the main Installer window, you begin with the Introduction pane, which contains important information about the requirements for installing Mac OS X and what you need to do before installing it. For example, it is likely to warn you about checking for firmware updates. Read the brief message and click Continue. You have now completed the Introduction.

License

Next up is the License pane, which provides the Software License Agreement for the software you're about to install. Agree to the terms and then move on.

Figure 3.7 The Select a Destination pane of the Installer, with a volume selected on which to install Mac OS X.

Figure 3.8 Installer refuses to install. The error message on the bottom appeared when trying to install Mac OS X on a volume that is currently the startup disk.

Select a Destination

Finally, we get to the first of the two critical panes for installing Mac OS X: Select a Destination.

In this pane, you will see an icon for every mounted volume (that is, each drive or partition of a drive). Some icons may include a symbol (such as an octagon with an exclamation point) indicating that you cannot currently install Mac OS X on that volume. If you do click the volume, a message will appear at the bottom of the window, indicating what the problem is and what you can do about it. One problem, for example, might be insufficient free disk space.

Once you've selected a volume, click the Options button at the bottom of the pane. A dialog will appear, providing the following installation options. Choose and then click OK:

Upgrade Mac OS X or Install Mac OS X. This option will read Upgrade OS X if your selected volume includes an updatable version of Mac OS X; using this option will install the necessary newer files on top of the existing installation. If you do not have an updatable version of Mac OS X installed, the option will read Install OS X; this will install a new copy of Mac OS X on the volume. Typically, the appropriate choice here is the default option—which means, for example, that you can bypass this Options pane if you know you intend to upgrade an existing Mac OS X installation. However, in some cases, such as if there is insufficient disk space to upgrade, this option will be dimmed and you will have to choose one of the remaining two. In addition, you may prefer to use one of the remaining options even if the Upgrade/Install option is available (see below).With either option (but especially the Upgrade option), the Installer just installs or replaces the OS files that are new or updated. Thus, any documents you created or third-party software you added should be preserved.

Archive and Install. This option is the one you will want if you are having any trouble with your current Mac OS X installation. Actually, you may want to use it instead of upgrading (I do!) as a way of preventing potential problems. Used for a volume that already contains some version of Mac OS X, archiving moves the existing OS software (essentially the System, Library, and Applications folders, plus all the invisible Unix folders) to a new folder named Previous Systems, located at the root level of your drive. One exception: Third-party software in the original Applications folder is not moved to the Previous Systems folder; instead it is transferred to your new Applications folder (which is typically what you would want!). The first time you do an Archive and Install, all the moved software is placed in a folder named Previous System 1 inside the Previous Systems folder. If you repeat this process, a Previous System 2 will be created and used, and so on. A new copy of Mac OS X software is installed in place of the moved copy.

This process also moves the Developer folder (if one is present) to Previous Systems. To replace this folder, you need to install the Developer Tools software separately.

A key sub-option here is Preserve Users and Network Settings. With this option selected, both the contents of the /Users folder (which contains your home directory!) and your Network settings are preserved. In almost all cases, I recommend selecting this option; if you don't, you'll have to re-create your accounts from scratch. About the only reason you wouldn't choose it would be if you thought files in your home directory were causing a problem, which you didn't want to carry over to the new installation.

In addition to preserving the contents of your /Users folder, this option also preserves your Network System Preferences settings. It may also preserve third-party software that would not get preserved via a standard Archive and Install (such as certain software in the Applications folder).

Note: This option does not preserve all system settings, just most of them. For example, it does not preserve the following: settings pertaining to whether a network time server is used; the list of configured printers (stored in /etc/printers.conf); the computer's time zone (stored in /etc/localtime); the resolution of your display(s), and other settings if more than one display is connected, such as arrangement (stored in the com.apple.windowserver.plist in /Library/Preferences and ~/Library/Preferences/ByHost/); and Sharing preference pane settings (stored in /etc/hostconfig). Most of this is minor stuff and can be easily reset if lost.

Note: If you proceed past the Select a Destination pane and then use the Back button to return, the Preserve Users and Network Settings option may be dimmed and unselectable. If so, select another volume (if possible) and then return to the original volume. Otherwise, you'll need to restart the Installer to reselect the option.

See

"Take Note: Why and How to Use Archive and Install," later in this chapter, for more details on this option.

Erase and Install. This option erases your drive and gives you the opportunity to reformat the volume as Mac OS X Extended (Journaled) or (the rarely used) Unix File System.

Obviously, you shouldn't choose this option if you're installing Mac OS X on a drive that includes software you don't want to erase.

Typically, you would select the Erase and Install option only if you suspected such severe drive problems that even a Mac OS X Archive and Install would be unable to fix them. In such cases, you would want to save any critical data on the drive before erasing it. To do this, start up from another hard drive or partition (assuming you can do so) and back up anything you want to save from the problem volume. Then relaunch the Install CD and perform an Erase and Install.

Avoid using Unix File System (UFS) unless you know you need it—and you almost certainly won't! For starters, Mac OS X Extended is the same format that Mac OS 9 uses. If you select UFS, you will not be able to use that partition for Mac OS 9. UFS drives also prevent some Mac OS X applications from working correctly. About the only people who might prefer UFS formatting are the select few running Mac OS X Server and thus working primarily with the Unix software in Mac OS X, not the Aqua applications.

Note: Alternatively, you can use Disk Utility to erase any volume (other than the current startup volume) at any time. To do so, launch Disk Utility, select the desired partition or disk, and click the Erase button. In the pane that appears, select a name and format for the volume, and click Erase. You can then use the Installer's Install Mac OS X option. This would be the approach you'd take if you wanted to use Disk Utility's "secure" erasure features (described in Chapter 2).

Some users recommend that you always select the Erase and Install option when you move to a major new OS version (such as from 10.3 to 10.4); however, I have not found this to be necessary.

See

"Disk Utility," in Chapter 2, for more details on using Erase, including additional format options available from here.

"Performing repairs with Disk Utility (First Aid)," in Chapter 5, for more on what journaled means.

Case-Sensitive HFS Formatting

If you're using Tiger (client or server) or Panther (server version only), when you format a drive you will be presented with an additional Format option: "Mac OS Extended (Case-sensitive)" (in Tiger) or "Case-sensitive HFS Plus (+)" (in Panther Server).

This format is exactly like the ordinary Mac OS Extended format, except that all file and folder names are case sensitive. That is, a folder with the name My Memos is seen as distinct from one named My Memos. In contrast, these names would be seen as the same name in standard Mac OS Extended—in fact, you couldn't even create two folders with these names in the same parent folder; instead, you would get a message saying the name already exists. (Note: Standard Mac OS X Extended remembers that the M in Memos is uppercase; however, the name is not treated differently in searches or file databases from one with a lowercase m.)

The main rationale for this is that Unix is case sensitive. By setting up a server to be similarly case sensitive, it eliminates some potential problems and inconsistencies between Mac OS X's Unix base and the higher-level user interface.

However, although it may make sense for certain server setups to use this format, you shouldn't use it in a client system unless you've got a specific reason to do so and are aware of the risks. Although most third-party disk utilities have been updated for compatibility with case-sensitive file systems, not all have, and using an incompatible one could result in data loss. A repair utility that is unaware of the case-sensitive format may assume that My Memos and My memos, if in the same location, are the same folder and delete one of them. In addition, few Mac OS X applications understand case-sensitive file systems.

Why and How to Use Archive and Install

The Archive and Install feature in Mac OS X is similar to the old Clean Install feature of Mac OS 9. Rather than updating an existing installation, it in essence creates an entirely new installation of system software.

Why Archive? You would use the Archive option for either of the following reasons:

The Installer refuses to update or reinstall Mac OS X, or you need to install an older version, and you don't want to reformat the drive. This option is especially helpful when reinstalling Mac OS X from the disc would be a downgrade from the existing OS version (say, because you updated to Mac OS X 10.4.1 via Software Update after installing 10.4.0 from the CD—you can't do a standard install of an older version of the OS). In Mac OS X 10.1.x, Apple strongly advised against doing any sort of downgrade installation, even if it seemed to be permitted by the Installer. At that time, Apple claimed that a downgrade could lead to the presence of files (especially Unix files and /System/Library files) from multiple OS versions in the same system—a potential source of conflicts. Apple's unwelcome solution was to erase your drive if you wanted or needed to do a downgrade installation. The Archive feature of newer versions of the Mac OS X Installer solves this dilemma. Now you can downgrade without erasing by using Archive and Install to install the older version and then update the new installation to the latest version.

You want to preserve files from the previous OS version. In some cases, you may worry that a simple upgrade will overwrite existing files that you may wish you had saved. For example, the Installer may install a new version of an application that contains a new bug. Going back to the old version may work around this bug until the inevitable bug-fix update is released. With the Archive function, the old application version is still in your Previous Systems folder and can be returned to active duty—assuming it works in Mac OS X. Similarly, you may want to replace some modified settings files—especially in the Unix software—with the new ones installed by Mac OS X, as detailed later in this sidebar.

For minor upgrades, such as from Mac OS X 10.4 to 10.4.1, the Options button is not available, meaning you cannot choose Archive and Install. Instead, your only option is Upgrade. However, if you're performing a major reference upgrade (that is, where there is a change in the first number after the decimal, such as from Mac OS X 10.3.x to 10.4.x), you will be presented with a choice of options. In this case, I recommend using the Archive and Install option and preserving the /Users folders, as described in the main text. There's very little downside to this option, other than the additional disk space required to store the archived software.

Reinstalling software and resetting preferences after an Archive installation. After an Archive and Install, you may need to reinstall some third-party software to get it to work properly. You may also need to reset some serial-number registrations. For example, I needed to re-enter my QuickTime Pro serial number.

As noted in the main text, you may also need to re-create some Mac OS X System Preferences settings. For example, when upgrading from Mac OS X 10.2.x to 10.3, I needed to reset the time zone in Date & Time, because it reverted to the Pacific time zone. I also had to re-enable the Network Time check in the same preferences pane.

Moving files after an Archive installation. After an Archive clean install, the archived OS software (in the Previous Systems folder) may contain a few files that you want to return to the now-current OS. As a general rule, I wouldn't move anything back until you discover that a setting or feature is missing and you can't re-create it easily by entering new settings. This way, you avoid the problems that can occur if you replace a needed newer file with an older one. That being said, included among the items you may want to move back are the following:

Files and folders in the old /Library folder. Files and folders that exist in your archived /Library folder but not in the updated /Library folder may contain additions and preferences files that you want to preserve. One example would be receipt files for third-party software in the Receipts folder. Another would be the StuffitEngineShell.cfm file, contained in the CFMSupport folder in /Library, which provides support for StuffIt Expander. Also, if you're running a Web server from your Mac but are storing your files in the system's Web directory rather than your user-level Web directory, you should transfer any custom contents of /Library/WebServer/Documents. Third-party items in the StartupItems folder are also not moved.Note: Sometimes, simply moving files from the old /Library folder to the new one doesn't work. For example, moving startup items from the previous /Library/StartupItems folder to your new /Library/StartupItems folder doesn't always work. You may need to reinstall the related software to install new copies of the StartupItems files. Another specific example: Some Palm Desktop users upgrading from Jaguar to Panther via Archive and Install found that after the upgrade, syncing no longer worked. The reason was that the HotSync Library files, located in /Library/CFMSupport, were not moved. Moving them manually did not fix the problem, either; the Palm software had to be reinstalled.

Certain applications. Some applications that require a password or registration code to function may not offer the option to re-enter the password. Instead, you may need to transfer an application's password/serial-number file from the Previous Systems folder. Otherwise, you may need to reinstall the application software.

If you do decide to transfer files back, you may be blocked from moving certain files due to insufficient permission access. In such cases, you will need to use techniques to modify permissions or authenticate the moves (such as those described in Chapter 6) so that you can bypass this blockade.

Deleting files after an Archive installation: Help files. You may want to delete some files that were carried over from the old home directory to the new one. If you are having problems with Help Viewer, for example, check out "Take Note: Getting Help for Help," in Chapter 2.

Transferring Unix files. Finally, you may have reason to move back some directories and files in Unix's invisible /private directory. In particular, you may want to move the following files and folders:

/etc/hostconfig. If you've set up Sendmail on your Mac, this file is important and probably should be restored from Previous Systems to the current Mac OS X folder. (Note, however, that Panther and later versions of Mac OS X use Postfix as their default Unix mail server, which means that this may be a good opportunity to switch, since Postfix has a much better reputation than Sendmail.)

/etc/httpd/httpd.conf. If you edited your Apache configuration (used for Web server preferences beyond those you can set up via the Sharing System Preferences pane), move this file back.

/var/root. If you enabled the root user in Mac OS X, this folder is the root user's /User folder: It contains the Desktop, Documents, and user-level Library directories, as well as any other files and folders that may have been created or saved to your home directory when you were logged in as root or using an application as root. If this folder contains any files you want to save, transfer them back.

You may need to log in as a root user or launch a file utility as root to make some of these changes.

Using the Previous Systems folder. One weakness of the Archive option is that the archived system is not bootable. In addition, the Installer does not offer a "switch back" option. Thus, if you decide that upgrading was a mistake (which is very unlikely!) and you want to return to the previous version of Mac OS X, there's no easy way to do a reverse exchange. For that reason, make sure that your Mac OS X volume is backed up before doing the upgrade. Then if you decide to go back, you can restore the old Mac OS X version from your backup.

Note: A third-party back-up program, Shirt Pocket's SuperDuper! (www.shirt-pocket.com), has a feature that offers the ability to switch back to a prior installed version of the OS.

Note: The application software in the Previous Systems folder—all older versions of "stock" Mac OS X applications that have been replaced by newer versions—remains functional. Thus, if you double-click a document that uses one of these applications and a newer version is not available elsewhere, the document will attempt to launch via the application in the Previous Systems folder.

Preserve Users and Network Settings. As I stated in the main text, I generally recommend using the Preserve Users and Network Settings option when doing an Archive and Install. But what if you did not use it and later wish you had? Good news: You can still restore your home directory; it will just be more work to do so. The directory is preserved in the /Previous Systems/Users folder. What you will need to do is create a new account for yourself, using the same short name as your old account. You can then copy files from the old account into the new one. You may need to reset permissions of some files, making yourself the owner, before you can use them. You can repeat this for any additional accounts you may have that you want to re-create.

Deleting Previous System (#) folder. After updating, you may eventually decide you no longer need any of the files stored in the Previous System 1 (or 2, and so on) folder and want to delete the folder to regain the disk space. If your account has administrator status, you can simply drag the folder to the Trash; if you're asked to authenticate, provide your user name and account password.

See

"Ownership & Permissions," in Chapter 4, for more on setting permissions.

"Opening and Saving: Permissions Problems," and "Copying and Moving: Permissions Problems," in Chapter 6, for more on setting permissions.

"Take Note: Deleting SystemConfiguration Folder Files," in Chapter 8, for more on where network settings are preserved.

Custom Config Files After a Mac OS X Update

When you make custom changes to a config file, the changes may be wiped out when you update to a new version of Mac OS X. This is because the update often replaces the customized config file with an updated default copy of the file. It will appear that all of your customized changes have been lost. In some cases, the Installer nicely preserves the customized file in the same directory, adding an extension to the filename, as in httpd.conf.applesaved or hostconfig.old. This allows you to recover your changes and add them back to the new file. Alternatively, you can swap the files so that the inactive file is returned to active duty. For example, for the httpd.conf files, give the active httpd.conf file a name like httpd.conf.base and rename the applesaved file as httpd.conf. Doing this httpd.conf change requires root access and should be done with Personal Web Sharing turned off.

However, starting with the installer package for the Mac OS X 10.2.5 Update, Apple reversed what happens when an update is installed, at least for the httpd.conf file. In describing this, Apple states, "Mac OS X 10.2.5 and later updates have a different installation method for the new httpd.conf file. The Installer checks to see if you have modified the existing httpd.conf file. If you have not, then it automatically replaces it with the new version. If you have modified it, then your modified file is left in place, and the new file is written as /etc/httpd/httpd.conf.default. At your leisure, you should add your modifications to the new file and retire the old one."

Major Mac OS X upgrades (typically defined as one in which the first digit after the decimal point changes, such as from 10.3 to 10.4) almost always require a new full-installation Mac OS X disc (a DVD or several CDs)—specifically, one that you must pay Apple to obtain. From this disc, you can install a new, full version of Mac OS X, even on an empty volume.

Between major updates, however, Apple releases minor updates. These free updates are available via Software Update or by downloading the update file from the Web. Such updates, however, can be applied only to already installed versions of Mac OS X (and sometimes only to the most recent prior version).

In some cases, Apple may offer an upgrade disc, such as via the Mac OS X Up-To-Date program (www.apple.com/macosx/uptodate), that differs slightly from the full install disc.

In the most extreme case, both the Install Mac OS X and Archive and Install options will be disabled on the upgrade disc. You will be able to upgrade only from an existing older version of Mac OS X. This limitation is significant, as it prevents you from using one of the key install features of Mac OS X: Archive and Install.

Tiger upgrade discs do include an Archive and Install option. However, it works only to upgrade a volume that is presently running Panther. You could not use this option, for example, to downgrade from Mac OS X 10.4.1 back to 10.4.0. You still cannot use the upgrade disc to install Mac OS X on a volume that does not already have an earlier version of Mac OS X installed. For such cases, you need the full Install disc.

See

"Cautions regarding extracting files from update packages," later in this chpater, for related information.

Installation Type, Install, and Finish Up

Finally, you'll reach the pane where you actually initiate the installation. By default, the Easy Install pane appears (unless your drive has insufficient disk space). If you're installing via CD, this pane informs you of whether you need Disc 2 and/or Disc 3 for the installation. At this point, you can simply click the Install (or Upgrade) button and then sit back and relax. You have now reached the Installation stage. The installation may take 20 minutes or so to complete, during which time a variety of status messages appear, informing you of what is happening at each stage. Unless something goes wrong and the installation fails, you're finished with the installation process. However, before you click the Install/Upgrade button, I recommend at least taking a look at the customization options, accessible via the Customize button.

Custom Install

Rather than doing an Easy Install, you can click the Customize button to bring up the Custom Install pane. From here, you can enable or disable individual components of the installation—which means you can disable options you don't need in order to save drive space or simply reduce clutter. This is also how you install software that would otherwise not be installed.

Custom Install options include the following:

Essential System Software. You cannot disable this option when installing Mac OS X; you can only do so when upgrading. And even then, I strongly advise against it—unless the only reason you're upgrading is to obtain a minor component of Mac OS X that you didn't install initially (such as a set of printer drivers).

BSD Subsystem. (Only an option in Panther and earlier installers.) The BSD Subsystem is made up of optional components of the otherwise essential Unix software at the core of Mac OS X (as discussed in Chapter 4). Although these components are technically optional, some applications may not run correctly without them. Again, other than for the reasons described above, I would never disable this option. (In Tiger and later installers, this option isn't even available—the BSD Subsystem is always installed.)

Additional Applications. (Only an option in Panther and earlier installers.) If you choose this option, you can omit the installation of specific applications such as Microsoft Internet Explorer.

Printer Drivers. From here, you can elect to omit specific printer drivers (such as those for particular brands of printers you do not own or expect to use). Panther also includes the option to install additional Gimp-Print drivers, used for adding Mac OS X support to otherwise unsupported printers (as covered in Chapter 7). (The Gimp-Print drivers are installed by default in Tiger.)

Additional Fonts. If you enable this option, fonts used by such languages as Chinese, Korean, Arabic, Hebrew, and a number of other non-Roman-alphabet languages will be installed.

Language Translations. These options provide the localized files and fonts that Mac OS X needs to support languages beyond English. If you're confident you don't need this support, disable these options. Doing so saves a significant amount of disk space—over 1 GB! I always choose a Custom Install over an Easy Install when I install Mac OS X for just this reason. If you want to just install files for one or two additional languages, you can do so; click the disclosure triangle for Localized Files and choose the languages you want installed.

X11. This installs the Unix X11 windowing system (see "Terminal and X11," in Chapter 2). This option is disabled by default, so you will need to do a Custom Install if you want to install it.

When you select a Custom Install option in the list, the bottom of the window shows a description of that item; to the right of the item you can see how much space it will require on your hard drive. When you're done configuring your Custom Install, click the Install button to begin installation. (If you change your mind and want to do an Easy Install instead, click the Easy Install button.)

Restarting

When installation is complete (and you reach the Finish Up pane), you can choose to restart by quitting the Installer. If you don't, the Installer will restart automatically after a brief delay.

When you restart, the Mac should start up from the volume where you just installed or upgraded Mac OS X. If it instead boots from the Install disc, restart again and hold down the Eject key (or mouse button) until the disc ejects. (If Disc 2 and/or Disc 3 are needed, you will be prompted to insert them at this point. The additional software on these discs is then installed.) If this is the first time you've installed Mac OS X (or if you did an Erase and Install or an Archive and Install without preserving user accounts), you will be prompted to set up an account for yourself, as well as Internet access, before you can log in. Otherwise, the Login window will appear or you will be automatically logged in, depending upon your preferences.

Checking for updates

Even if you've just installed Mac OS X, there may be minor updates that are newer than the installed version. For this reason, once you've successfully installed Mac OS X, you should run Software Update to check for and then install any updates. (If you're connected to the Internet on login, Software Update may launch automatically.)

Alternatively, if you previously downloaded the update files, you can install them directly from the .pkg files.

At this point, you can also install the Developer software from the Xcode Tools folder on the Install DVD. Updates to the Developer software are not listed in Software Update. Instead, you must check Apple's Developer Web site (http://developer.apple.com/tools) for updates to this software.